The assembly of wheels for use in castors or the like has been a process which has incorporated many steps and which have, over the years, been considered standard procedural steps in assemblying the wheel. More specifically, wheels were placed into jigs and the bearing assembly was assembled into the hole normally provided in the center of the wheel. The assembly of the wheel necessitated that the hole normally provided in the center of the wheel be concentric with the outer diameter of the wheel. Normal manufacturing tolerances for the wheel in some cases were exceeded and after the wheel became assembled and placed into an environment, such as a shopping cart, a normal use of the nonconcentrically arranged bearing assembly and wheel would then generate a wobbling or loping as the cart was being utilized. The wobbling or loping characteristic generates a self-destructive condition on the bearings. Many efforts have been made to solve the problem of properly aligning the axis of rotation of the bearing assembly with the center of the outer diameter of the wheel but this has continued to be a problem in view of the manufacturing tolerances generally controlled by the manufacturer of the wheel. If the wheel is made of a hard rubber composition, a separate supplier for the wheel is utilized and the manufacturer of the wheel assembly generally has no control over the normal manufacturing tolerances of the wheel supplier. Thus, the manufacturer of the wheel assembly is rendered somewhat helpless in solving a problem that has existed for many years.
Accordingly, it is an object of this invention to provide a method and apparatus for assemblying a bearing assembly having bearing means therein into a hole in the center of the wheel and assuring that the axis of rotation of the bearing assembly is coaxial with the center of the outer diameter of the wheel.
It is a further object of this invention to provide a method and apparatus, as aforesaid, wherein a spacing is provided between the outer periphery of the bearing assembly and the inner wall surface of the hole in the wheel and, during assembly, aligning the center of the outer diameter of the wheel with the axis of rotation of the bearing assembly and thereafter filling the spacing with moldable, synthetic resin material to effect, upon a congealing of the moldable, synthetic resin material, a securement of the bearing assembly in the hole in the wheel and thereby assuring that the outer diameter of the wheel is concentric with the axis of rotation of the bearing assembly.
It is a further object of this invention to provide a method and apparatus, as aforesaid, utilizing a mold into which the bearing assembly and the wheel is placed to effect the proper alignment between the axis of the bearing assembly and the center of the outer diameter of the wheel so that the moldable, synthetic resin material can be properly guided into the spacing therebetween.
It is a further object of this invention to provide a method and apparatus, as aforesaid, wherein the assembly of the bearing assembly into the hole of the wheel can be performed by a minimum of operating personnel.
It is a further object of this invention to provide a method and apparatus, as aforesaid, which is easily maintained and effects a very rapid production of wheel assemblies.
It is a further object of this invention to provide a method and apparatus, as aforesaid, which effectively reduces the unit of assembly time per operating personnel per wheel assembly.